TraceListener Filter have zero effect

I've triple checked my work, read all the threads I can find here and done plenty of googling and I still don't understand why the LAB is completely ignoring a Filter I have set on a TraceListener.

When I log information severity items they are being emailed - it's as if the "Critical" filter does nothing at all. More likely I'm missing something or confused, but I have no idea what I'm doing wrong.